Rewiring: Knob and Tube Wiring

From the 1880s to the 1930s, knob and tube wiring was the standard electrical wiring system used in most North American buildings. Designed as an open-air system, the single-insulated copper conductors ran through walls or ceilings and were supported by ceramic knob insulators, which served to separate wires from combustible framing. Today, however, knob and…